|
Use of the low-dose corticotropin stimulation
test for the diagnosis of secondary adrenocortical insufficiency
CH Choi, SC Tiu, CC Shek,
KL Choi, FKW Chan, PS Kong
Department of Medicine, Queen Elizabeth Hospital
OBJECTIVE. To assess the clinical utility and safety
of the low-dose corticotropin stimulation test in the diagnosis
of secondary adrenocortical insufficiency.
DESIGN. Prospective study.
SETTING. Regional hospital, Hong Kong.
PARTICIPANTS. Seventy-two Chinese patients with suspected secondary
adrenocortical insufficiency.
MAIN OUTCOME MEASURE. Serum cortisol response during the low-dose
corticotropin stimulation test, using the insulin tolerance test
as the gold standard.
RESULTS. The 30-minute cortisol level during the low-dose corticotropin
stimulation test was most closely correlated (r=0.79) with the peak
cortisol level achieved during the insulin tolerance test. The optimum
sensitivity and specificity of the low-dose corticotropin stimulation
test were obtained at a cut-off value of 550 nmol/L or more for
the 30-minute cortisol level. Using the insulin tolerance test as
the gold standard for comparison, the low-dose corticotropin stimulation
test had a sensitivity of 97%, a specificity of 78%, a positive
predictive value of 81%, and a negative predictive value of 97%
at this cut-off value. The positive likelihood ratio was 4.4 and
the negative likelihood ratio 0.04.
CONCLUSION. The low-dose corticotropin stimulation test, using the
cortisol response at 30 minutes after synacthen 1 µg is a
safe, convenient, and sensitive method for screening abnormalities
of the hypothalamic-pituitary-adrenocortical axis in Chinese patients
suspected of having secondary adrenocortical insufficiency.
Hong Kong Med J 2002;8:427-34
Key words: Adrenal gland hypofunction; Corticotropin;
Diagnosis
|
